This invention is in the field of articles of manufacture made from composites; more particularly the invention relates to a helmet comprising an impact resistant composite shell.
Helmets having impact resistance and in particular ballistic impact resistance are known in the art. Attempts are continually made to improve the impact and ballistic resistance of such helmets.
A variety of helmets and methods for making helmets are described in publications such as U.S. Pat. No. 4,199,388 and G.B. Patent application No. 2,098,852. As shown in the UK reference attempts are continually made to design the composite using reinforced fabric cut from flat sheets which must be formed into the three dimensional spherical like shape of a helmet. The fibrous composite should be formed into a helmet without the fabric wrinkling. At the same time there should be no weaknesses along seams and edges in the fabric which occur to obtain a three-dimensional form.
In the design of composites made from high strength fibers a useful article of manufacture typically considered is a helmet. This is the case for example in commonly assigned U.S. Pat. Nos. 4,403,012,; 4,457,985; 4,501,856; 4,613,535; 4,623,574; 4,650,710 as well as commonly assigned filed patent applications having U.S. Ser. No. 081,260, filed Aug. 3, 1987 now U.S. Pat. No. 4,820,568 and U.S. Ser. No. 081,074, filed Aug. 3, 1987 now abandoned.
U.S. Pat. No. 4,309,487 discloses ballistic resistant laminates of polyethylene fibers where the fibers in each layer are unidirectional and at an angle to fibers in adjacent layers. The laminates are made in the absence of adhesives with each layer being at least 0.5 mils thick. A six inch by six inch square film laminate is disclosed in the Examples. U.S. Pat. No. 4,079,161 is of interest.